In a surprising find by Swedish researchers, alleged Arabic characters were found woven into the burial costumes found from Viking boat graves, as well as the chamber grave clothing of central Viking Age sites, such as Birka. The garments were kept in storage for more than a century—dismissed as being typical Viking Age funeral clothing—until a new investigation yielded much more intriguing results.

“One exciting detail is the word ‘Allah’ depicted in mirror image,” says the textile archaeologist who made the breakthrough discovery, Annika Larsson of Uppsala University.

Larsson's findings have not undergone peer review and have been disputed by some other archaeologists since word of the discovery first emerged late last week.

The patterns were woven in silver thread on bands of silk. Larsson says that, presumably, Viking Age burial customs were influenced by Islam, as well as the idea of an eternal life in paradise after death. Larsson says she’s studied many silk finds from Central Asian areas. Written sources indicate that some “Vikings” actually came from those areas, she says, while Scandinavia was a kind of western outpost of the Silk Road.

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“In the Quran, it is written that the inhabitants of paradise will wear garments of silk, which, along with the text band’s inscriptions, may help explain the widespread occurrence of silk in Viking Age graves,” says Larsson. She also noted that the findings were equally prevalent among both men’s and women’s graves. (See how DNA shed new light on Viking gender roles.)

Larsson says the tiny geometric designs on the funeral garments were like nothing she had ever come across in Scandinavia. She believes that they were not actually Viking patterns, but ancient Arabic Kufic script.

Unlocking the puzzle of the text meant enlarging the letters and examining them from all angles, including from behind. One of the words that kept recurring was identified as the name Ali, the fourth caliph of Islam, as well as the Arabic word for God, Allah.

What excites Larsson about the find is the new “lens” she can now put on while examining Viking artifacts. “Textiles and clothing can tell more about people’s intangible values and imaginations than many other archaeological finds,” she says. Armed with that information, she hopes to contribute new knowledge and a broader perspective.

In a press release posted by Uppsala University, Larsson notes that it is often presumed that Eastern objects in Viking Age graves were a result of plundering. But Larsson believes that the Kufic lettering was perhaps an attempt to write prayers to be read from left to right.

The phrase “for Allah” was once identified as being inscribed on a silver ring found in a female tomb in Birka. But the woven inscription found recently by Larsson is the first-ever Kufic symbol for the name “Ali” found in all of Scandinavia.

While the exact meaning of the inscriptions is unknown, Larsson told the BBC that “the possibility that some of those in the graves were Muslim cannot be completely ruled out.” She says the discovery is important “for increased understanding of complex historical events, with a high relevance for integration and to counteract xenophobic currents.”

Advanced technologies, from satellite imagery to DNA studies and isotope analysis, are helping archaeologists and other scientists to find surprising new answers about an ancient culture shrouded in mystery. Viking fortune seekers often ventured far from their home shores of Scandinavia, equipped with sleek sailing ships and a vast seafaring knowledge. They are known to have visited more than 37 countries, from Afghanistan to Canada.

Skeptical Voices

Since this story was first published, Larsson's study has been disputed by some archaeologists, including textile archaeologist Carolyn Priest-Dorman, who wrote a critical blog post. The garments show some signs of reconstruction, wrote Priest-Dorman, including a "selvedge," or finished hem.

Stephennie Mulder, a professor of Islamic Art and Architecture at the University of Texas at Austin, also remains skeptical. While Mulder says she cannot fully assess Larsson's findings until she sees her entire publication, it would take a lot to convince her that the garments indeed included Kufic script reading "Allah." She says that the particular Arabic letter form that Larsson claims to have identified doesn't actually appear until 500 years following the creation of the 10th century Viking textile.

Mulder concludes, "The word Allah is definitely not there. Instead of a letter 'A' there you actually have a letter 'L,' which reads as nonsense. It would essentially be the difference between the words dog and god. As much as you want it to read god it just doesn't."

Still, Mulder says, "There is a deeper foundation of truth here. There really were interactions between Vikings, Muslims, and the Islamic World. Some people would even call Scandinavia the final outpost on the Silk Route."

Note: This story was updated at 2 pm ET on October 17 with additional comments from archaeologists who are skeptical of Larsson's findings.